The sounds of protests over abortion issues at state Capitols across the country are fading as legislatures conclude divisive debates over new restrictions. But advocates on both sides of the issue are quietly watching to see how another volatile fight will soon play — this one over how insurers will choose to cover abortion in new marketplaces under the health care law.

The marketplaces, which are also known as exchanges, will start enrolling people on Oct. 1 and begin providing health insurance coverage to consumers on Jan. 1. The federal health care law to some extent puts the choice about abortion coverage in the hands of insurers — most of whom have made their decisions but not announced them.

Already, critics of abortion have passed laws in 22 states that ban any abortion coverage in the exchanges.

North Carolina may be next. Both chambers passed different versions of a bill that restricts abortion, and one of the provisions under discussion would limit coverage in the marketplaces. The North Carolina bill was one of several that sparked controversy this year in state capitals from Madison, Wis., to Austin, Texas.

While the state battles have captured national interest, the decisions by insurers have not.

“This threat has gotten almost no attention,” said Donna Crane, vice president of policy at the National Abortion Rights Action League, a group that promotes access to abortion.

In states that have not banned abortion coverage in the marketplaces, abortion rights groups have sought to influence insurance commissioners and insurers through discussions about the law. The National Women’s Law Center is providing a two-page explainer that aims to help insurers meet the law’s requirements on abortion with the least amount of hassle possible.

Supporters of restrictions on abortion say they are eagerly waiting to find out more about insurers’ decisions.

“We haven’t talked directly to insurance companies, but we have some concerns,” said Mary Harned, staff counsel for Americans United for Life. “Basically one of the key things when the [health care law] was enacted was that there’d be consumer choice. When concerns over abortion coverage were raised, the reply was people in exchanges would have a choice of plans that cover abortion or don’t. Unless you’re in a state that opted out, what we’re seeing is a lot of the promises of choices are falling away.”

Perhaps the one thing that each side has in common is that both make the same passionate argument about limited choices.

So far, the landscape is mixed. In the 22 states that have banned abortion coverage in the exchanges, insurers cannot offer it. A few other states — including California and Connecticut — take the opposite approach and require plans to cover “medically necessary” abortions, in which a physician determines whether an abortion is needed for a health-related reason.

In other places, many insurers are continuing their typical practice of covering abortion for people who buy insurance on their own or through coverage for small companies. That’s the case for all the plans in Washington state and Vermont.

But not all are. Aetna Inc., one of the nation’s largest insurers, does not plan to cover abortion in the District of Columbia exchange, according to district officials, and reportedly in other states. Aetna officials did not respond to requests for comment. Other insurers in the D.C. marketplace — CareFirst BlueCross BlueShield, Kaiser Permanente and UnitedHealth Group — will offer plans that cover abortion.

During the 2010 debate over the law, questions about abortion coverage in the marketplaces were among the last to be settled. More than a dozen House Democrats who wanted more abortion limits almost derailed the law’s final passage when they threatened to oppose the bill.

Democrats on both sides of the issue aimed to continue the Hyde amendment, a provision added every year since the 1970s to the Labor-HHS-Education spending bill covering Medicaid and insurance for federal workers that bans federal dollars from paying for abortions except in cases of rape, incest or danger to the woman’s life.

A group of House Democrats led by then-Rep. Bart Stupak of Michigan sought to require women who got federal subsidies for insurance to buy a separate abortion policy rider with their own money if they wanted. But the Senate changed the language. The final version requires payments for abortion coverage to be separate from money for the rest of insurance so it is clear that no federal money supports abortion. The law said workers using direct deposit for their insurance must make separate deposits.

The House Democratic critics backed the bill when President Barack Obama signed an executive order confirming that tax credits and subsidies for copays or deductibles cannot fund abortion services through the exchanges, except in cases of rape, incest or risks to the life of the woman.

Groups that back abortion rights such as the National Women’s Law Center say that the provision requiring separate “payments” does not actually mean that customers — including men — must write two separate checks, one for insurance and another for abortion coverage. They are telling insurers they can collect one check and segregate the money internally later.

They base their interpretation on an April 24 memo from the Centers for Medicare and Medicaid Services, which oversees the health law, that says “there are no regulatory requirements governing the content of an issuer’s premium billing invoice for enrollees of the individual exchange.”

The question of whether consumers must make two separate payments is important because if customers must write two checks, it would be harder for insurers to administer abortion coverage and might irritate consumers who don’t want to pay for it.

Another twist is that the health law allows for multistate plans in each exchange. At least one multistate plan is supposed to cover abortion and another is not. But the multistate plans — which were intended to boost competition and serve as an alternative to the “public option” that many liberals wanted — are being phased in. Officials at the CMS and the Office of Personnel Management are not requiring two plans in each state right away.

The way that the requirement is operating in practice is that if there is only one multistate plan in a marketplace, as is the case in the D.C. exchange, then OPM officials are ensuring that the plan does not cover abortion. CareFirst will cover abortion in its Washington-specific plan, but not in its multistate plan. OPM and CareFirst officials declined to comment.

CMS officials said in an email that the multistate plans will help them “ensure that in each exchange, there is at least one plan available that covers abortions beyond those allowed by the Hyde Amendment and at least one plan that does not cover abortions beyond those permitted by the Hyde Amendment,” such as cases of rape, incest or danger to the woman’s life.

None of these issues has gotten scrutiny in the past year, but that is likely to change as the launch of the marketplaces approaches.

“As things get closer this fall, attention on the abortion funding issue is going to increase,” said David Christensen, senior director for congressional affairs for the Family Research Council, which opposes abortion.